The present disclosure relates to a memory element and a memory device which store information based on any change of electrical characteristics observed in a memory layer including an ion source layer and a resistance change layer.
A semiconductor nonvolatile memory popularly used for data storage has been a NOR or NAND flash memory. Such a semiconductor nonvolatile memory, however, has been pointed out that there are limitations on microfabrication considering the need for a high level of voltage for writing and erasing, and the limited number of electrons injected into a floating gate.
For overcoming such limitations on microfabrication, a next-generation nonvolatile memory currently proposed is a resistance change memory such as ReRAM (Resistance Random Access Memory) or PRAM (Phase-Change Random Access Memory) (for example, see Japanese Unexamined Patent Application Publication No. 2006-196537, and Waser et. al., Advanced Material, 21, p 2932 (2009). These memories are each in the simple configuration including a resistance change layer between two electrodes. In the memory of Japanese Unexamined Patent Application Publication No. 2006-196537, as an alternative to the resistance change layer, an ion source layer and an oxide film (thin film for storage) are provided between first and second electrodes. These resistance change memories are each formed therein with a conductive path through migration of atoms or ions by heat or an electric field, whereby a resistance value is supposed to change. For reference, see Japanese Unexamined Patent Application Publication No. 2009-43757.